Integrated microcircuit chips or dies are commonly manufactured in a wafer form whereby a large number of identical dies are built on a single substrate or wafer.
It has been found advantageous to pretest the dies in their wafer configuration rather than waiting until the dies are singulated and mounted on a leadframe, or even packaged and readied for shipment. Such a preliminary testing may involve so-called "wafer lever burn-in" wherein the dies are subjected to static and/or dynamic electrical testing under various power supply levels, temperatures and other environmental conditions. The wafer testing is usually accomplished by means of a probe having a plurality of fingers positioned to contact various points on the surface of the wafer. The conditioning of the microcircuits for various types of testing requires that the operating modes of the circuits be controlled by signals fed to the wafer through some of those contact fingers and control leads added to the wafer circuits.
It would be advantageous to find other means to condition the dies for various types of testing without having to dedicate some of the usually limited number of probe contact fingers for such controlling operations.
The majority of microelectronic circuits, and specially CMOS circuit used in high speed digital processes are sensitive to variations in the level of their supply voltage. Not only is it necessary to regulate the supply voltage fed to the microcircuits so that it remains constant within upper and lower limits of the available power source, but it is important to monitor the level of said power source in order to condition the circuits to withstand variations in the level of said power source beyond those set limits.
It would thus be advantageous to use a voltage regulator circuit for microelectronic devices which could not only regulate the available power supply but also detect excessive variations in the power source beyond a safe margin of operating voltages.